Background: Areca-nut (AN) chewing habit has been associated with oral diseases including oral cancer, oral submucous fibrosis and periodontal disease; however, some authors have reported that the AN-chewing abuse may also jeopardize the systemic health among its users. Objectives: The objective was to review any reported association between AN-chewing and the metabolic syndrome (MetS). Methods: To address the research question "Is there an association between areca-nut chewing habit and the MetS?" the MEDLINE and PubMed databases were searched from 1991 up to and including April 2010. The search criteria included: human studies, metabolic syndrome, diabetes, areca nut (AN). Only articles published in English were included. Results: Eight cohort studies were included in the review. The sample size of the selected studies ranged from 210 to 56,116 individuals (age range 15-83 years). The daily frequencies of AN-chewing reported by the users ranged between once a day to 76 times daily. The duration of use ranged from 6 years to ≥ 20 years. Two studies associated AN-chewing habit with hyperglycemia and type 2 diabetes while five studies studies reported an association between AN-chewing and metabolic syndrome. Four studies related AN-chewing with obesity and an increased body mass index. Higher triacylglycerol levels were reported in one study among AN-chewers compared to non-chewers. Though the numbers of publications on this subject are limited, the available studies indicate that AN-chewing could be associated with the metabolic syndrome, and individually with two of the recognized components of the syndrome i.e. diabetes mellitus and central obesity.